// 导出页面为PDF格式

import html2canvas from "html2canvas"

import JSPDF from "jspdf"

export default {

install (Vue) {

Vue.prototype.ExportSavePdf = function (htmlTitle, currentTime) {

var element = document.getElementById("pdfCentent")

html2canvas(element, {

logging: false

}).then(function (canvas) {

var pdf = new JSPDF("p", "mm", "a4") // A4纸，纵向

var ctx = canvas.getContext("2d")

var a4w = 170; var a4h = 257 // A4大小，210mm x 297mm，四边各保留20mm的边距，显示区域170x257

var imgHeight = Math.floor(a4h * canvas.width / a4w) // 按A4显示比例换算一页图像的像素高度

var renderedHeight = 0

while (renderedHeight < canvas.height) {

var page = document.createElement("canvas")

page.width = canvas.width

page.height = Math.min(imgHeight, canvas.height - renderedHeight)// 可能内容不足一页

// 用getImageData剪裁指定区域，并画到前面创建的canvas对象中

page.getContext("2d").putImageData(ctx.getImageData(0, renderedHeight, canvas.width, Math.min(imgHeight, canvas.height - renderedHeight)), 0, 0)

pdf.addImage(page.toDataURL("image/jpeg", 1.0), "JPEG", 10, 10, a4w, Math.min(a4h, a4w * page.height / page.width)) // 添加图像到页面，保留10mm边距

renderedHeight += imgHeight

if (renderedHeight < canvas.height) { pdf.addPage() }// 如果后面还有内容，添加一个空页

// delete page;

}

pdf.save(htmlTitle + currentTime)

})

}

}

}